Printing-telegraph



F. RITCHIE.

PRINTING TELEGRAPH.

APPLICATIQN FILED AUG.6, I918- 1,4 00,988, v Patented Dec. 20,1921.

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wze ss a6 F. RITCHIE.

PRINTING TELEGRAPH.

APPLICATION FILED AUG. 5, I918- Patented Dec. 20, 1921.

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APPLICATION FILED AUG.6, I918.

Patented Dec. 20,1921.

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jwwi? Z51 ZZZ a 6 iJNlTED STATES PATENT i t lCE.

FOSTER RITCHIE, 0F EALING, ENGLAND.

PRINTING-TELEGRAPH.

Application filed August 6, 1918. Serial No. 248,617.

To all whom it may concern:

Be it known that I, Fosrnn RITCHIE, a subject of the King of GreatBritain, residing in Ealing, England, have invented a certain new anduseful Improved Printing-Telegraph, of which the following is aspecification. V

The invention relates to an improved printing telegraph, adapted for useover a two-wire telegraph or telephone line. According to the invention,at the receiving station the line is earthed and on each side of theearthed connection are arranged a polarized and a non-polarized relay.The line is thereby divided into two independent circuits and theselection of the required character is determined by the currentstransmitted simultaneously from the sending station over the two wiresof the line and operating the appropriate relays on either side of theearthed connection.

From the sending station, by the actuation of suitable keys, directcurrents of which the strength and polarity are varied according to thesignals to be transmitted are simultaneously and independently sent overeach wire of the line. For example, over one section there may be a weaknegative current and over the other section at the same time a strongpositive current.

The relays on either side of the earthed connection are energizedaccording to the currents received in their respective wires andcontrolthe circuits of relays disposed in two local circuits,corresponding respectively to the two wires of the line. The relays inthe local circuits control contacts in the circuits of electro-magnetsfor actuating the type levers.

If there are four relays in each local circuit, any one ofQlelectro-magnets can be energized by the different combinations formed.

Also, according to the invention, each type lever is provided with twotype characters, either of which can, when the arm is actuated, recordan impression according to the position of the paper on which theimpres' sions are recorded. The position of the paper carrierisdetermined by a shift electro-magnet energized by an alternating orintermittent current transmitted from the sending station andsuperimposed on the direct currents sent over the line. The alternatingor intermittent currents are received by a condenser in series with arelay bridgwill not be affected by these currents, either because oftheir greater inductance, or because they are constructed ascomparatively slow acting relays which do not respond to the shortduration of the paper shifting impulses.

The operation of each type lever is controlled by a valve which admitsair to and exhausts it from a cylinder containing a piston connected tothe lever. The position of the valve depends upon whether theelectromagnet associated with the particular type lever is, or is not,energized.

In the system according to the invention, the great advantage is gainedthat no successive impulses and no synchronizing apparatus are required;each signal sent from the transmitting station effects a combination ofenergized relays which causes the instantaneous impression of thedesired character and enables great speed of working to be attained. Theaccompanying drawings illustrate diagrammatically an example of aprintin telegraph according to the invention. *igure 1 represents thecircuits at the transmitting station, Fig. 2 shows the line wire andlocal relay circuits at the receiving station, Fig. 3 shows theconnection between the local relay circuits and the electro-inagnets foractuating the type levers; Fig. 4 represents an example of the means foroperating these levers pneumatically; Fig. 5 shows in diagram thegeneral arrangement of the circuits at either station.

Referring to Fig. 1, A, B, are the terminals of the line wires. K is oneof the 24 keys which when depressed closes its contacts a, b andtransmits to the line Wires connected to A and B respectively currentsfrom a source of electricity which is shown as a battery 13 but whichmay be a motor generator, the strength and polarity of the currentsbeing determined by the connections of the springs c and d with theconductors 10,:1: and y, c. In the position shown,

the key K when depressed will cause a strong negative current to flowover the line connected to the terminal B and a weak positive current toflow over the line connected to the terminal A. The strength of thecurrent is determined by the'insertion or omission of the resistance RR, from their respective circuits. The line wires are connected at thereceiving station to terminal A,,B bridged by polarized relays P P andby non-polarized relays NQN, connected as shown. The line is earthed atBelays G, .D, E, F are included in a local circuit controlled by therelays 1'? and N, and relays H, I, J, are included in a local circuitcontrolled by the relays P, and N the batteryB forms a source of energyfor both local circuits. T he armatures 29 1 2 take up mid positions, asshown in Fig. 5, when the relays P and P are not energized.

With'the connections assumed in Fig. 1, the armatures n 2),, a 0, willrest against their respective contacts as shown in Fig. 2. Relays F andG will be energized and the electro-magnet 18 will also be energized ina circuit from 13,, contact 7",, electro-magnet 13, closed contact 9 to13,. If F and H were energized, electro-magnet 14 would be energized; 7Fand I energized'would energize electro-Inagnet 15'; F and J energizedwould energize 16. The number of electro-magnets that can be energizedwhen either of the relays C, D, E, F is separately energized and a relayof the set G, H, I, J, is also energized at the same time isconsequently 16.-

If F were energized but no relay of the other local circuit,electro-magnet 20 would be energized; if none of the relays C, D, E, Fare energized, one of the electro-magnets 21, 22,

23, 24 is energized. If the corresponding relay of the set' G, H, I, Jis energized, and if none or the relays G, H, I, J are energized one ofthe electro-magnets 17, 18, 19, 20 is energized, if the correspondingrelay of the set C, D, E, F is energized. The totalnumber of differentelectro-magnets that can be energized with this combination of relays isconsequently 24c.

It will be seen from Fig. 4, that each type lever U carries in knownmanner two type characters It and To print the character j at the end ofthe lever it is necessary that the paper carrier is should be raised soas to bring the paper is, opposite j and clear of h when the type leverhas been brought into the operative position shown by the dotted lines.

The shift of the paper referred' to above is effected through anelectro-magnet which is energized by an alternating or intermittentcurrent transmitted trdm the 1 ioones .minals A 13,; the inductance ofthe relays N N P P 'prevents any appreciable portion of the-alternatingcurrents from passing to earth at Q. The armature 0 of relay 0 normallyrests against its back contact and thereby short circuits a relay'Z.When relay O is energized, the short circuit is removed, relay Z isenergized by a battery B, over aresistance B and by attracting itsarmature a so as to close the frontcontact 2 energizes an electrdmagnetX which effects the paper shift.

The electrormagnets eiiect the lifting of the type levers through themedium of a pneumatic device. In Fig. 4 M represents one of the magnets1 to 2d; when the magnet M is energized, its armature m is attracted andby moving a valve 4) to the right, against a seat 8, allows compressedair to enter a cylinder i through a seat 8 against which the valve isnormally pressed in contact by a spring 0. The compressed air drives apistcn Z and type lever U to which it is pivoted by the rod Z to theprinting position shown by the dotted lines. f

WVhen the magnet M is deenergized the valve 4) isrestored to the seat 8and an exhaust path is formed .for the air in the cylinder 2' past theseat 8 A spring 6 returns the type lever to the normal position.

In a similar way the paper carrier la is raised by a piston Z operatedby an electro magnet X included in the circuit of the relay Z (Fig. 2).The pneumatic device for operating the lever is not broadly new and isnot claimed herein.

' As the signalstransmitted must be recorded at the transmitting as wellas at the receiving station, apparatus similar to that shown in Fig. 2is connected for this purpose to the terminals A and B in shunt with thelines to the receiving station or stations. Resistances R R, as shown inFig. 5 are inserted between the transmitting and re cording apparatuscorresponding to the line resistance, these resistances being cutoutwhen signals are belng received, a key T mechanically connected to. allthe transmitting keys being provided to insert these resistances whenrequired. 7 i k The inking of the type is efiected by a ribbon inthemanner usual with typewriting machines.

' The paper feed is effected by a pneumatic device of the kind describedand is connected as shown at Y (Fig. 3).

To bring this into action without printing which is required whenspacing, one of the numbers 1 to 24 is represented by a re sistance, sothat in the example shown there are 23 type levers, enabling 46characters to be impressed.

Having thus described the nature of the said invention and the bestmeans I know of carrying the same into practical effect, I claim 1. Aprinting telegraph in which the impression of a character may beeffected by the actuation of a single key at the transmitting stationand in which direct currents of different polarity and strength aretransmitted and received independently and simultaneously over the leadsof a two wire line, a polarized and a neutral relay inserted in each ofthe said leads at the receiving station and means by which analternating current may be superimposed on the direct current traversingeach lead.

2. in a printing telegraph a receiving instrument comprising a two leadwire con nected with the transmitting station, a polarized and a neutralrelay in each lead, a local source of current, four local relaysassociated with each lead, means whereby not more than one of the saidfour local relays associated with the same lead is energized at anytime, and connections whereby the relays associated with one lead areenergized in parallel in pairs with the relays associated with the otherlead.

3. A printing telegraph in which direct currents of diil'erent polarityand strength are transmitted and received independently andsimultaneously over the leads of a two wire line, a polarized and aneutral relay being inserted in each of the said leads at the receivingstation, a transformer comprising primary and secondary coils, a key atthe transmitting station, means by which the actuation of said keycauses the primary coil to be intermittently energized and to inducealternating currents in the secondary coil which are conveyed over eachlead of the line, a paper carrier at the receiving station and means bywhich said alternating currents shift the position of said papercarrier.

i. A printing telegraph in which direct currents of different polarityand strength are transmitted and received independently andsimultaneously over the leads of a two wire line, a polarized and aneutral relay being inserted in each of the said leads at the receivingstation, a transformer comprising primary and secondary coils, a key atthe transmitting station and means by which the actuation of said keycauses the primary coil to be intermittently energized and to inducealternating currents in the secondary coils which are conveyed over eachlead of the line, a relay bridging the line wires at the receivingstation and energized by said alternating currents, a local circuit atsaid receiving station, an electromagnet in said local circuit energizedwhen said relay is energized, a paper carrier and means operated by saidelectromagnet for shifting said paper carrier.

A printing telegraph station and transmitter thereat, comprising incombination keys corresponding to the characters to be transmitted, atwo wire lead from the station, a resistance in each line wire, keys forshort circuiting said resistances, a source of direct current fortransmitting currents of varying strength over each line wire, a primarycoil and means for intermittently energizing said coil from said source,secondary coils energized from said primary coil transmittingalternating currents over said two wire lead, a paper carrier at thereceiving station and means by which said alternating currents shift theposition of said paper carrier.

6. A printing telegraph station and receiver thereat comprising incombination a two wire lead, a polarized and a neutral relay in eachlead energized by direct currents, a relay bridging the said line wiresin series with a condenser and energized by alternating currentssuperimposed 011 said direct currents, a local circuit, means by whichthe local circuit is closed when said relay is energized, anelectro-magnet energized in said local circuit, type levers eachcarrying two sets of type characters, and a paper carrier shifted bysaid electromagnet so as to bring the paper opposite the required set ofcharacters.

In testimony whereof I have signed my name to this specification.

FOSTER RITCHIE.

